8 Growing Microbes 9/16-9/22

Procedure

1) Making Nutrient Agar Plates

1. Perform calculations to determine how much powdered media to use:
   1. If each plate holds 25 mL agar, how much agar is needed for 5 plates?  (A: 125 mL agar)
   2. To make 1 L (1000 mL), you would use 40 g of nutrient agar media mixed into 1 L of water.
   3. To make 125 mL agar,  how many g of media would you need? (A: 0.125 L (125 mL) water x 40g agar = 5 g agar media)
2. Use the weigh boat to measure out 5 g of nutrient agar using your scale (make sure to zero it first).
3. Using your scale to measure out  125 mL of water in a microwavable cup.
   1. Set your microwavable cup on your scale and tare it.
   2. Add water to your cup until the scale reads 25 g.
   3. Measure out 25 g 5x so you have 125 mL total (NOTE: the scale has a limit so you need to weigh out 5 amounts of 25mL; 1 g = 1 mL)
4. Heat the water for 30 seconds- a minute in the microwave until boiling. BE CAREFUL NOT TO BURN YOUR HANDS WHEN WORKING WITH HOT WATER AND MEDIA.
5. Immediately mix in the powdered media and swirl the container with the tongue depressor.
6. Once cooled down to almost room temperature, pour roughly 25mL into each plate.
7. Once the media has become solid, invert and refrigerate all five plates to prevent contamination..
8. Keep the plates made for the Isolating Microbes module.

Results:

I forgot to take photos. 🙁

Nutrient agar (NA) is a general-purpose medium designed to support the growth of a wide range of microorganisms. It contains key ingredients like peptones, sodium chloride, beef extract, and agar, which provide essential nutrients, maintain osmotic balance, and solidify the medium. After preparing and cooling the nutrient agar, it should solidify to form a firm surface for microbial growth. If contamination is absent, a pure culture will show uniform colonies, while a mixed culture will result in colonies of varying shapes, sizes, and colors. The typical agar concentration in nutrient agar is around 1.5%, and this can be calculated by measuring the amount of agar used in the medium.

Selective media, unlike nutrient agar, is designed to favor the growth of specific microorganisms while inhibiting others, such as MacConkey Agar for Gram-negative bacteria. Differential media, such as EMB agar, allows for the identification of different microorganisms based on their biochemical activities, like lactose fermentation. TSA, like nutrient agar, is a general-purpose medium, though it may support a broader range of organisms due to its enriched nutrient content. Understanding the components and purpose of each medium type is essential for effectively managing microbial cultures and ensuring accurate experimental results.

answer to the growing microbes question:

Growing Microbes Assignment-1